Nuclear protein, matrix and structural changes in rooster liver after estrogenic induction of vitellogenesis
Nuclear protein, matrix and structural changes in rooster liver after estrogenic induction of vitellogenesis
复制标题
雌激素诱导卵黄发生后公鸡肝脏核蛋白、基质和结构的变化
作者：
K. Brasch;K. E. Peters
雌激素对鸟类和两栖类动物肝脏卵黄发生的诱导作用在靶基因水平上已经得到了很好的表征。然而，对与反应相关的同源核事件知之甚少，特别是涉及大规模结构变化和非组蛋白蛋白（NHP）的事件。我们已经在初级刺激公鸡中进一步研究了这些方面。在第一个24小时后诱导雌二醇，肝细胞核扩大了50%，并表现出急剧上升的总蛋白和RNA含量。特别是，残留NHP的质量增加了约40%。广泛的内部重组是明显的，包括部分解聚的染色质，染色质间的成分和突出的“核体”从头出现的增殖。这些变化伴随着核质和几个基质组分蛋白质的定量波动。在所有三种核纤层蛋白以及约75和约175 kD蛋白质中明显相对降低。然而，Hn-RNP-相关多肽和各种未鉴定的组分变得更加突出。到24小时，细胞完全分化，大量输出卵黄蛋白原和低密度脂蛋白。所有变化持续数天，然后在2 - 4周内逐渐恢复正常。然而，许多关键的核修饰并没有完全消退，包括持续增大、NHP含量升高和修饰的基质组分蛋白。总的来说，这些可能反映了“记忆”效应的一部分，通常在类固醇靶组织中观察到，由此在初级诱导消退后很长时间内可以触发第二个更明显的反应。
The estrogenic induction of vitellogenesis in avian and amphibian liver has been well characterized at the target gene level. Comparatively little however, is known about cognate nuclear events associated with the response, particularly those involving large‐scale structural changes and the non‐histone proteins (NHP). We have examined these aspects further in primary stimulated roosters. In the first 24 hr post induction with estradiol, hepatocyte nuclei enlarged by 50% and exhibited sharp rises in total protein and RNA content. In particular, the mass of residual NHP rose about 40%. Extensive internal reorganization was evident, including partial disaggregation of chromatin, proliferation of interchromatin components and de novo appearance of prominent “nuclear bodies”. These changes were accompanied by quantitative fluctuations in nucleoplasmic and several matrix fraction proteins. A marked relative decrease was evident in all three lamins, as well as approximately 75 and approximately 175 kD proteins. Hn‐RNP‐associated polypeptides however, and various unidentified components became much more prominent. By 24 hr, cells were fully differentiated for bulk export of vitellogenin and low density lipoproteins. All changes persisted for several days before gradually regressing to normal over a 2‐4 week period. Many key nuclear modifications, however, did not regress fully, including persistent enlargement, elevated NHP content and modified matrix fraction proteins. Collectively, these may reflect part of the “memory” effect, commonly observed in steroid target tissues, whereby a second, more pronounced response can be triggered long after primary induction has subsided.